1. Field of the Invention
The present invention relates to a system for the electrochemical conversion of polyols to hydrocarbon (HC) products and to methods for making and using same.
More particularly, the present invention relates to a regenerable system for the electrochemical conversion of polyols, especially from biomass or other waste products, to hydrocarbon (HC) products such as combustible HC fuels, where the system comprises a coupled electrochemical reduction including a reduction of polyols to hydrocarbons or iodohydrocarbons and a concurrent oxidation of HI to I2. These primary reactions are coupled to a secondary electrochemical reaction that converts I2 back to HI via the oxidation of a metal from a reduced oxidation state to a oxidized oxidation state, e.g., V2+ to V3+. The system is regenerated by reducing the spent metal from is oxidized state back to its reduced state, e.g., V3+ back to V2+, providing a continuous electrochemical system for polyol reduction. The invention also relates to a method for converting polyols, in particular polyols derived from biomass, into hydrocarbons that can be burned as fuels.
2. Description of the Related Art
Efficient utilization of biomass as an industrial feedstock will result in a renewable and sustainable resource for chemicals and liquid transport fuels (see, e.g., Chum, H. L.; Oserend. R. P. Fuel Processing Technology, 2001, 71, 187). Previously, the inventor showed that polyols, produced directly from biomass carbohydrate polymers using catalytic hydrogenolysis, could subsequently be reduced by a concentrated HI solution when an added co-reducing agent such as H3PO2 or H3PO3 was present to rapidly transform incipient I2 into HI (U.S. Pat. No. 5,516,960 (1996)). However, the H3PO4 byproduct was not easily regenerated, which with industrial sized plants could become a problematic waste (Robinson. J. M.; Herndon, P. T.; Holland, P. L.; Marrufo. L. D. “Regeneration and Recovery of Hydriodic Acid after Reduction of Polyols to Fuels”, Organ. Process Res. &. Dev. 1999, 3(5), 352).
Thus, there is a need in the art for a readily regenerable system for electrochemical conversion of polyols from biomass to more useful hydrocarbon (HC) products such as combustible fuels.